code: def test_iadd():
      style = Style(color="red")
      style += Style(bold=True)
      assert style == Style(color="red", bold=True)
      style += None
      assert style == Style(color="red", bold=True)
  
imports: import pytest
  from rich import errors
  from rich.color import Color, ColorSystem, ColorType
  from rich.style import Style, StyleStack
label_desc: Use image node_id 18 for calling a global function with example usage: test_iadd() without return types